Federal, state and local law enforcement agencies are increasingly borrowing border-patrol drones for domestic surveillance operations, newly released records show, a harbinger of what is expected to become the commonplace use of unmanned aircraft by police.

Customs and Border Protection, which has the largest U.S. drone fleet of its kind outside the Defense Department, flew nearly 700 such surveillance missions on behalf of other agencies from 2010 to 2012, according to flight logs released recently in response to a Freedom of Information Act lawsuit filed by the Electronic Frontier Foundation, a civil-liberties group.

The records show that the border-­patrol drones are being commissioned by other agencies more often than previously known. Most of the missions are performed for the Coast Guard, the Drug Enforcement Administration and immigration authorities. But they also aid in disaster relief and in the search for marijuana crops, methamphetamine labs and missing persons, among other missions not directly related to border protection.

Because they have sophisticated cameras and can remain in flight for many hours at a time, drones create novel privacy challenges. Civil libertarians have argued that these aircraft could lead to persistent visual surveillance of Americans on private property. Government lawyers have argued, however, that there is no meaningful legal distinction between the use of unmanned and piloted aircraft for surveillance.

I think it is true that using a drone and using a piloted aircraft are about the same in principle. But using aircraft was far less common. Now that we have cheaper drones to deploy, what was an occasional use of air surveillance now might become constant. It isn’t hard to understand that the courts might want to re-think our tolerance for air surveillance if it is suddenly possible to monitor Americans around the clock.

What seems most worrisome about this article is that we wouldn’t know about the hundreds of missions flown with drones if it wasn’t for the lawsuit filed by the Electronic Frontier Foundation. They forced the authorities to release the information.

The logs, which were heavily redacted before being released, detail hundreds of missions and attempted missions. In every case, the name of the government agency borrowing the drones was blacked out, but CBP officials separately provided overall totals of how often various agencies used its drones.

So far, only Customs and Border Protection has permission to fly drones and all other law enforcement agencies can only request help from the Border Patrol. But is that situation going to last, or are other agencies going to have their own drone-flying privileges.

When a branch of government decides to routinely patrol with drones, rather than use them only in investigations, will we be first informed of that decision? One big difference between foot and car patrols, and drones, is that policemen walk and drive in public property. They can’t look over our privacy fences.

But airborne drones can routinely fly over private property. That is a game changer that should be openly discussed before drones become widely implemented.